Thin film solar cells are one of the important candidates utilized to reduce the cost of photovoltaic production by minimizing the usage of active materials. However, low light absorption due to low absorption coefficient and/or insufficient active layer thickness can limit the performance of thin film solar cells. Increasing the absorption of light that can be converted into electrical current in thin film solar cells is crucial for enhancing the overall efficiency and in reducing the cost. Therefore, light trapping strategies play a significant role in achieving this goal. The main objectives of light trapping techniques are to decrease incident light reflection, increase the light absorption, and modify the optical response of the device for use in different applications. Nanostructures utilize key sets of approaches to achieve these objectives, including gradual refractive index matching, and coupling incident light into guided modes and localized plasmon resonances, as well as surface plasmon polariton modes. In this review, we discuss some of the recent developments in the design and implementation of nanostructures for light trapping in solar cells. These include the development of solar cells containing photonic and plasmonic nanostructures. The distinct benefits and challenges of these schemes are also explained and discussed.

• Klíčová slova
• light trapping, photonic nanostructures, plasmonic nanostructures, solar cells, thin films,
• Publikační typ
• časopisecké články MeSH
• přehledy MeSH

Photoelectrochemical (PEC) water splitting is a promising approach for producing hydrogen without greenhouse gas emissions. Despite decades of unceasing efforts, the efficiency of PEC devices based on earth-abundant semiconductors is still limited by their low light absorption, low charge mobility, high charge-carrier recombination, and reduced diffusion length. Plasmonics has recently emerged as an effective approach for overcoming these limitations, although a full understanding of the involved physical mechanisms remains elusive. Here, the reported plasmonic effects are outlined, such as resonant energy transfer, scattering, hot electron injection, guided modes, and photonic effects, as well as the less investigated catalytic and thermal effects used in PEC water splitting. In each section, the fundamentals are reviewed and the most representative examples are discussed, illustrating possible future developments for achieving improved efficiency of plasmonic photoelectrodes.

• Klíčová slova
• hydrogen production, photoelectrochemistry, photonic nanostructures, surface plasmons, water splitting,
• Publikační typ
• časopisecké články MeSH
• přehledy MeSH

DNA nanotechnology has emerged as a groundbreaking field, using DNA as a scaffold to create nanostructures with customizable properties. These DNA nanostructures hold potential across various domains, from biomedicine to studying ionizing radiation-matter interactions at the nanoscale. This review explores how the various types of radiation, covering a spectrum from electrons and photons at sub-excitation energies to ion beams with high-linear energy transfer influence the structural integrity of DNA origami nanostructures. We discuss both direct effects and those mediated by secondary species like low-energy electrons (LEEs) and reactive oxygen species (ROS). Further we discuss the possibilities for applying radiation in modulating and controlling structural changes. Based on experimental insights, we identify current challenges in characterizing the responses of DNA nanostructures to radiation and outline further areas for investigation. This review not only clarifies the complex dynamics between ionizing radiation and DNA origami but also suggests new strategies for designing DNA nanostructures optimized for applications exposed to various qualities of ionizing radiation and their resulting byproducts.

• Klíčová slova
• DNA damage, DNA structures, Nanostructures, Nanotechnology,
• MeSH
• DNA * chemie   MeSH
• elektrony MeSH
• ionizující záření MeSH
• konformace nukleové kyseliny účinky záření   MeSH
• nanostruktury * chemie   MeSH
• nanotechnologie * MeSH
• reaktivní formy kyslíku chemie   MeSH
• Publikační typ
• časopisecké články MeSH
• přehledy MeSH
• Názvy látek
• DNA * MeSH
• reaktivní formy kyslíku MeSH

Nanophotonic devices, which control light in subwavelength volumes and enhance light-matter interactions, have opened up exciting prospects for biosensing. Numerous nanophotonic biosensors have emerged to address the limitations of the current bioanalytical methods in terms of sensitivity, throughput, ease-of-use and miniaturization. In this Review, we provide an overview of the recent developments of label-free nanophotonic biosensors using evanescent-field-based sensing with plasmon resonances in metals and Mie resonances in dielectrics. We highlight the prospects of achieving an improved sensor performance and added functionalities by leveraging nanostructures and on-chip and optoelectronic integration, as well as microfluidics, biochemistry and data science toolkits. We also discuss open challenges in nanophotonic biosensing, such as reducing the overall cost and handling of complex biological samples, and provide an outlook for future opportunities to improve these technologies and thereby increase their impact in terms of improving health and safety.

• MeSH
• analýza nákladů a výnosů MeSH
• biosenzitivní techniky * ekonomika   MeSH
• elektromagnetická pole MeSH
• fotony * MeSH
• nanostruktury chemie   MeSH
• spektrální analýza MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• přehledy MeSH

A lot of insect families have physical structures created by evolution for coloration. These structures are a source of ideas for new bio-inspired materials. The aim of this study was to quantitatively characterize the micromorphology of butterfly wings scales using atomic force microscopy and multifractal analysis. Two types of butterflies, Euploea mulciber ("striped blue crow") and Morpho didius ("giant blue morpho"), were studied. The three-dimensional (3D) surface texture of the butterfly wings scales was investigated focusing on two areas: where the perceived colors strongly depend on and where they do not depend on the viewing angle. The results highlight a correlation between the surface coloration and 3D surface microtexture of butterfly wings scales.

• Klíčová slova
• 3D surface morphology, Butterfly wings scales, Multifractal analysis, Photonic nanoarchitectures, Scanning probe microscopy,
• MeSH
• biologické modely MeSH
• fraktály MeSH
• křídla zvířecí ultrastruktura   MeSH
• matematické pojmy MeSH
• mikroskopie atomárních sil MeSH
• motýli ultrastruktura   MeSH
• nanostruktury ultrastruktura   MeSH
• pigmentace MeSH
• povrchové vlastnosti MeSH
• zobrazování trojrozměrné MeSH
• zvířata MeSH
• zvířecí šupiny ultrastruktura   MeSH
• Check Tag
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH

This work describes a novel method for converting bismuth triiodide (BiI3) microplates into bismuth oxyiodide (BiOI) nanoflakes under ultrasonic irradiation. To produce BiOI nanoflakes with a high yield and high purity, the conversion process was carefully adjusted. Rapid reaction kinetics and increased mass transfer are benefits of the ultrasonic-assisted approach that result in well-defined converted BiOI nanostructures with superior characteristics. The produced BiOI nanoflakes were examined utilizing a range of analytical methods, such as Transmission Electron Microscopy (TEM), scanning electron microscopy (SEM) and X-ray diffraction (XRD). The progress in the ultrasonic conversion process with time was monitored through diffuse reflectance spectroscopy (DRS). The outcomes demonstrated the effective conversion of BiI3 microplates into crystalline, homogeneous, high-surface-area BiOI nanoflakes. Additionally, the degradation of organic dyes (methylene blue) under ultraviolet (UV) light irradiation was used to assess the photocatalytic efficacy of the produced BiOI nanoflakes. Because of their distinct morphology and electrical structure, the BiOI nanoflakes remarkably demonstrated remarkable photocatalytic activity, outperforming traditional photocatalysts. The ability of BiOI nanoflakes to effectively separate and utilize visible light photons makes them a viable option for environmental remediation applications. This work not only shows the promise of BiOI nanoflakes for sustainable photocatalytic applications but also demonstrates a simple and scalable approach to their manufacturing. The knowledge gathered from this work opens up new avenues for investigating ultrasonic-assisted techniques for creating sophisticated nanomaterials with customized characteristics for a range of technological uses.

• Klíčová slova
• bismuth oxyiodide, bismuth triiodide, methylene blue, photocatalytic, ultrasonic irradiation,
• MeSH
• bismut * chemie   MeSH
• difrakce rentgenového záření metody   MeSH
• fotochemické procesy MeSH
• jodidy chemie   MeSH
• katalýza MeSH
• methylenová modř chemie   MeSH
• nanostruktury * chemie   MeSH
• ultrafialové záření MeSH
• ultrazvuk metody   MeSH
• ultrazvukové vlny MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• bismut * MeSH
• bismuth oxychloride MeSH Prohlížeč
• jodidy MeSH
• methylenová modř MeSH

Cerium 4f level occupation determines the properties of cerium oxide based catalysts in a significant way. The Ce 4f level of nanosized cerium oxide particles was investigated with the use of resonant photoelectron spectroscopy in the Ce 4d-4f photoabsorption region. A strong interaction of ceria with different additives, e.g. Pd and Sn, led to a partial Ce4+-->Ce3+ transition that was observed as a significant resonance enhancement of 4f photoemission intensity. Increases of the CO oxidation catalytic activity were observed simultaneously. The ratio of resonance enhancement of Ce photoemission intensity DCe(3+)/DCe(4+) was used to monitor Ce(3+) and Ce(4+) state occupation. The relative parameter DCe(3+)/DCe(4+) was found to be particularly useful in the case of photoemission studies of nanopowder ceria catalysts.

• MeSH
• cer chemie   účinky záření   MeSH
• chemické modely * MeSH
• fotony MeSH
• krystalizace metody   MeSH
• makromolekulární látky chemie   MeSH
• molekulární konformace MeSH
• nanostruktury chemie   účinky záření   ultrastruktura   MeSH
• nanotechnologie metody   MeSH
• počítačová simulace MeSH
• povrchové vlastnosti MeSH
• světlo MeSH
• testování materiálů MeSH
• velikost částic MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• cer MeSH
• ceric oxide MeSH Prohlížeč
• makromolekulární látky MeSH

Zn K edge and O K edge x-ray absorption near-edge structure (XANES) spectra of ZnO surfaces are calculated. The difference between theoretical XANES for ZnO surfaces and ZnO bulk is then compared to the earlier observed differences between experimental XANES for ZnO nanostructures and ZnO bulk as taken from the literature. It follows from our calculations that the differences between the experimental XANES of bulk ZnO and nanocrystalline ZnO is not due to the enhanced role of the surfaces in nanostructures. Rather, the difference in XANES has to reflect differences in the local geometry around the photoabsorbing sites. The dependence of XANES of ZnO surfaces on the polarization of the incoming radiation is also investigated theoretically and found to be similar as in the bulk.

• MeSH
• absorpce MeSH
• elektronika MeSH
• krystalizace MeSH
• molekulární konformace MeSH
• nanočástice MeSH
• nanotechnologie metody   MeSH
• nanotrubičky MeSH
• optika a fotonika * MeSH
• oxid zinečnatý chemie   MeSH
• povrchové vlastnosti MeSH
• rentgenové záření MeSH
• spektrometrie rentgenová emisní metody   MeSH
• zinek chemie   MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• oxid zinečnatý MeSH
• zinek MeSH

Stacking mismatches in hexagonal boron nitride (h-BN) nanostructures affect their photonic, mechanical, and thermal properties. To access information about the stacked configuration of layered ensembles, highly sophisticated techniques like X-ray photoemission spectroscopy or electron microscopy are necessary. Here, instead, by taking advantage of the geometrical and chemical nature of h-BN, we show how simple structural models, based on shortened interplanar distances, can produce effective charge densities. Accounting these in the non-analytical part of the lattice dynamical description makes it possible to access information about the composition of differently stacked variants in experimental samples characterized by infrared spectroscopy. The results are obtained by density functional theory and confirmed by various functionals and pseudopotential approximations. Even though the method is shown using h-BN, the conclusions are more general and show how effective dielectric models can be considered as valuable theoretical pathways for the vibrational structure of any layered material.

• Publikační typ
• časopisecké články MeSH

We report the creation of a functional nanostructure on a Si crystal surface by 200 keV C60(++) cluster ion bombardment (CIB). We found that the modified layer produced by CIB includes two sublayers with different nanostructures. The top 24-nm-thick sublayer is an agglomeration of 5-nm-sized amorphous Si nanodots (a-Si NDs). The deeper 10-nm-thick sublayer is a transient layer of disordered Si as an interface between the a-Si top sublayer and the bulk Si(100). The top a-Si sublayer and the nc-Si transient layer are formed by the local heating effect and shock wave effect, respectively, induced by the cluster ion impacts. The photoluminescence (PL) spectra of the CIB-modified Si samples revealed an emission line centered at a photon energy of 1.92 eV. The absorption spectra of the modified samples exhibit enhanced light absorption at this photon energy. The parameters of the PL line require ascribing the emission origin to the quantum-confinement-induced optical transitions in the a-Si nanodots. The core-shell structure of a-Si NDs is confirmed by detection of an additional PL line centered at 2.5 eV. Analysis of the Rutherford backscattering (RBS) and the PL spectra implies the existence of -Si--O- bonds in the nanodot outer shells, which are responsible for the additional PL line. The obtained results demonstrate the valuable potential of CIB for the controllable fabrication of Si surface nanostructures, which is attractive for optoelectronics and nanoelectronics. The obtained results elucidate the evolution of structure modification occurring in silicon due to the injection of energetic C60 cluster ions with an energy of hundreds of keV.

• Publikační typ
• časopisecké články MeSH